Lamp cutout



June 15, 1948. 'H. E. BUTLER 2,443,442

LAMP cur-our Filed Feb. 25, 1947 2 Sheets-Sheet 1 Invehtor: H envy E.Butler,

by His Attorn ey.

June 15, 1948. H. E. BUTLER 2,443,442

LAMP CUT-OUT Filed Feb. 25, 1947' 2 Sheets-Sheet 2 Ifiventow": Henry E.But/19.1,

H IS Attorney.

Patented June 15, 1948 LAMP CUTOUT Henry a. miner, Seotia, N. Y m to amElectric Company, a nflation New York Application February as, an, seemNo. msso 1 My invention relates to electric lamp cut-outs,

and more particularly tomagazine rod type film cut-outs for electriclamp shunting contacts.

In series electric lighting circuits and the like. it is usual toprovide in each lamp base a pair of resilient lamp shunting prongs, orcontacts, arranged normally to be insulated from each other by a cut-outelement including a film of copper oxide or other voltage-limitingdielectric medium which is subject to electrical break-down upon theoccurrence of a predetermined excessive voltage. A typical lamp basewith such shunting contacts is illustrated in Patent 2,078,793, issuedto H. J. Flaherty on April 27, 1937. The type of cut-out elementcurrently generally used is a small disk or wafer-like elementcomprising a pair of conducting buttons normally separated by a copperoxide film. Such wafer-like cut-out elements, while highly effective andsatisfactory in operation, are generally rather difilcult to handlebecause of their small size. These elements are commonly about the sizeof a five or ten cent piece, and must often be handled by a linesmanwearing a pair of bulky insulating gloves.

Accordingly, it is a principal object of my. in-- vention to provides.new and improved magazine rod type electric lamp cut-out which may bereadily removed and replaced without individual handling of the separatecut-out elements.

It is a particular object of my invention to provide a new and improved,sectionalized rod type, magazine cut-out element which may be readilyhandled by an operator wearing bulky insulating gloves.

My invention itself will be more fully understood and its variousobjects and advantages further appreciated by referring now to thefollowing detailed specification taken in conjunction with theaccompanying drawing in which Fig. 1 is a cut-away perspective view of amagazine type cut-out embodying my invention; Fig. 2 is a crosssectionalview taken along the line 2--2 of Fig. 1; Fig. 3 is an end view of asingle contact element of the cut-out shown at Figs. 1 and 2; Fig. 4 isa cross-sectional view taken along the line 4-4 of Fig. 3; Fig. 5 is aperspective view illustrating the manner in which the cut-out elementsof Figs. 1 to 4 are inserted between lamp prongs; Fig. 6 is across-sectional view of a film cut-out rod similar to that of Fig. i butillustrating another embodiment of my invention; Fig. 7 is a side viewofa film cut-out rod illustrating a further embodiment of my invention;Fig. 8 is a cross-sectional view taken along the lines 8-. of Fig. 7;Fig. 9 is a side view of a film cut-out rod 4 Claims. (Cl. sot-11s) 2illustrating still another embodiment. of my invention; m. 10 is aemu-sectional view taken along the line l'l-ll of Fig. 9; Fig. 11 is aperspective view showing the film cut-out of Fig. 9 inserted between apair of lamp shunting prongs: Fig. 1-2 is a side view of. a film cut-outrod illustrating still mother embodiment of my invention; and Fig. 13 isa cross-sectional view taken along the line lI-II of '18. 12.

Referring now to the drawins. and particularly, to Figs. 1-5, inclusive,I have there shown one embodiment of my invention comprising a pluralityof film cut-outs I formed as sections of a rigid sectionalized rod ofmoulded insulating material 2, the rod being substantially cylindricalin cross-section and having spaced apart portions 3 of reducedcross-sectional area. The sectionalizing portions 8 or the insulatingrod, being of reduced cross-sectional area, are of less mechanicalstrength than e intermediate sections of th rod. and thus facilitateseparation of the various sectional cut-outs. The insulating rod ispreferablyof oblate cross-sectional eonfigm'ation, as illustrated atFigs. 1. 2 and 5, to facilitate proper positioning of the cut-outbetween a pair of lamp shunting prongs 4 and i, as illustrated at Fig.5.

The individual cut-outs are formed by setting into each rod section I,as by moulding or the like, a pair of electric conducting imerts orconso tact bri ging pins 8, the pins being disposed transversely'of therod 2 in end-to-end relation with their outer ends protruding slightlyon opposite sides of the insulating rod. The protruding outer ends ofthe pins 8 provide contact with the lamp prongs 4 and I. Theadjacentinner ends of the contact bridging pins 0 are normally insulatedfrom each other by a thin film l of copper oxide or other suitablevoltage-limiting dielectric medium characterized by electrical breakdownat a predetermined voltage. To ensure retention of the pins I in themoulded rod 2, the inner ends oi the pins 0 are flanged as at I.

At Figs. 3 and 4, I have shown detailed views of a single bridging pin6. It will be observed that in the embodimentfof the invention shown atFigs. 1-5, each pin 6 is formed as a flanged cup having its innersurface coated with a thin film I of copper oxide. The bridging pins 3are moulded into the rod 2 with their flanged ends adjacent and theirclosed ends protruding from opposite sides'of the rod.

At Fig. 5, I have illustrated the manner in which a film cut-out sectionsuch as shown at Figs. 1-4 is positioned between a pair of resilientlamp shunting prongs 4 and I. In inserting a cutment'with oppositeprongs! broken oil at the next sectionalizlng portion 3,

4 derstood that I intend in the appended claims to cover all suchmodifications which fall within the true spirit and scope of myinvention.

leaving the inserted cut-out in place between prongs. It is evident fromFig. 5, that in replacing a used or defective cut'out, the end 01 thesectionalized rod or cut-outs may itself be used to eject the oldcut-out while inserting the new 1 cut-out;

AtFig. 6, Ihave shown a cross-sectional view shown at Fig. 1, but inwhich the contact bridg 'ing pins 6 are set into the 'rod sections withtheir flanged ends outward and their'closed' ends ad-" What I claim asnew and desire to secure by Letters Patent oi the United States, is:

1. A magazine rod type cut-out for insertion between electric lampshunting prongs comprisor a sectionalized cut-out rod similar to thatcular cross-section and provided at one side with a radially protrudingpositioning flange 9. The

, conducting inserts or brid ing pins 0 are inserted with their flangedends outward as at Fig. 6, and are of rectangular rather than circularcrosssection, as illustrated at Fig. 7.

At Figs. 9 and 10, I have illustrated still a further embodiment of myinvention in which the sectionalized rod of insulating material 2 has across-sectional configuration similar to the rod of Figs. 7 and 8, butin which the bridgin inserts or pins 8 are or circular cross-section andmoulded into the rod in the manner ot-the. pins 8 at Fig. 8.

At Fig. 11, I have shown a fragmentary perspective view of a pair oflamp shunting prongs I and 5 having clamped therebetween a sectionalprotect the oxide coating 13 from damage by en-- gagement with thecontact prongs I provide outer sectional electrode coating it of metalon opposite sides of each rod section. The sectional metallic electrodecoatings it serve to protect the copper oxide film-from adverse weatherconditions and irom chipping by abrasion. The sectionalized cut-out ofFigs. 12 and 13 may be used in conjunction with shunting prongs or thetype shown at Figs. 5 and 11. In this' form of the invention apositioning flange l or a position determining configuration or thecut-out is desirable to ensure that the electrode coatings ll engage theprong contacts 4 and 5.

While I have described'only certain preferred embodiments of myinvention by way or illustration; many modifications will occur to thoseskilled in the art and I, therefore, wish to have it immg a rigidsectionalized rod of insulating material substantially cylindrical incross-section having set into each section a transverse bridging pinformed of a pair of electrically conductive inserts normally insulatedfrom each other by a voltage-limiting dielectric medium.

2. A magazine rod type cut-out for insertion between electric lampshunting prongs comprising a rigid sectionalized rod of mouldedinsulatin material, said rod having spaced apart separating portions orreduced cross-sectional area and being or substantially uniformcross-sectional configuration between said portions, and a pair 01'electric conducting bridging inserts set into each section or said rodtransversely in end to end relation and normally insulated from eachother solely by a voltage-limiting dielectric film, said inserts havinghead portions protruding from opposite sides of said rod for engagementwith said prongs.

3. A magazine rod type film cut-out for insertion between electric lampshunting prongs comprising a rigid sectionalized rod oi mouldedinsulating material, said rod having spaced apart separating portions ofreduced cross-sectional area and being of substantially uniformcrosssectional configuration between said portions, each section of saidrod having set therein a pair of contact bridging pins disposedtransversely in end-to-end relation and having head portions protrudingfrom opposite sides of said rod for engagement with said prongs, theadjacent ends or said pins being normally insulated from each other by afilm of copper oxide. I

4. A magazine rod type cut-out for insertion between electric lampshunting prongs comprising asubstantially cylindrical rigidsectionalized rod or moulded insulating material having spaced apartseparating portions of reduced mechanical strength, each section of saidrod having moulded therein a pair oi transversely disposed electricconducting inserts in end-to-cnd relation, the ad- Jacent ends or saidinserts being normally insulated from each other by a film of copperoxide and the remote ends of said inserts protruding from opposite sidesof said rod for engagement with said prongs.

HENRY E. BUTLER.

narnnancns man The followingv references areof record in the file orthis patent:

UNITED STATES PATENTS" ,Swartz Sept. 19, 1939

